Hitching devices which permit a tractor or similar vehicle to connect to a wagon or the like have been known for many years. Many types of hitches have been developed including those having laterally opposed jaws and a pivotable hook member mounted therebetween with a spring biasing the hook member into the closed position. An upstanding pin may be provided on the tongue of the wagon or other vehicle to be towed and the tractor connects to the pin by backing the hitch against the pin. If the hook member has a tapered head, the pin will push the hook member open and the hitch may be automatically coupled onto the wagon while the operator remains in the cab of the tractor.
Some hitches have been provided with release mechanisms which permit the operator to retract the hook member from a remote location such as the cab and unhitch the wagon from the tractor. This permits a farmer to quickly and easily pick up and move wagons, drop them off, and return for other wagons all without leaving the cab or seat of the tractor. Not only does this save time, but it is a significant improvement over other types of hitching mechanisms which require that flanges or the like be aligned with matching flanges on the tractor and a pin be manually inserted before the tractor is hitched to the wagon. However, one of the advantages of the manual type hitch is that safety locks and catches may be easily provided to ensure that the wagon is locked onto the tractor and is not merely dependent upon the spring which urges the hook member into the closed position. It can be appreciated that with the automatic hitches, a manual safety lock would essentially defeat the purpose of the automatic hitch as it would require the operator of the tractor to dismount and engage or disengage the manual lock each time the wagon is hitched or unhitched. Furthermore, is is unlikely that a manual lock provided on an automatic hitch would be used as the typical operator would just not take the time to see that it is properly engaged and disengaged for each hitching operation.
Applicant has succeeded in inventing a safety lock mechanism which may be provided on an automatic hitch and which does not interfere with its automatic operation. The safety lock provides a back up, double lock which holds the hook member in the closed position and prevents the accidental loss of a wagon while towing even should the spring operator of the hook member be damaged or disabled. Furthermore, applicant's safety lock may be remotely operated in combination with the remote hook member operator so that completely automatic operation is retained. To ensure completely safe operation, the safety lock is spring biased into the locked position which provides "dead man" safety override should the operating mechanism be damaged.
Applicant has also designed an automatic hitching mechanism to accommodate the use of the safety lock. This hitch includes many desirable features such as a tapered hook head to provide for automatic engagement of a pin, completely automatic hitch operation including a remotely operable release for the hook member, heavy duty pivot for the hook member including an integral ball type hitch, heavy duty mounting plate suitable for mounting the hitch to various types of vehicles, shock absorbers to isolate the hitch from the vehicle, suitable for orientation in any plane including vertical for use with various types of tongues, and other features as are more fully described in the preferred embodiment.